【摘要】 三角形连接的链式H桥逆变器对于配合大容量可再生能源及储能的并网具有很好的应用前景。但链式结构中相互独立的直流侧各自并联有参数不一致的负载或电源,造成了直流侧电压不平衡的问题,严重制约了装置的可靠运行。在电网不平衡的条件下,分别使用零序电流注入和分相控制法分析了三角形连接中各单相功率模型,并比较了两种方法的优缺点。通过提出一种零序和负序电流混合注入的分相控制方法,将零序电流注入和分相控制统一在传统的电流解耦控制下,并在此基础上提出了一种结合零序电流注入和分相控制的相间直流侧平衡控制方法。通过仿真和实验表明了该方法的有效性和可行性,结果表明该方法较好地兼顾了装置的输出性能和相间功率调节能力。更多还原

【Abstract】 Cascaded H-bridge grid-connected inverter with delta configuration has good application prospects in grid connection for large-capacity renewable energy and electrical energy storage. However, DC voltage balancing problem restricts the reliable operation of the equipment, which is brought by the different parameters of paralleling load or power source in each isolated DC side. This paper analyzes active power models of three phases under unbalanced grid condition by using zero-sequence current injection and individual phase control method, and then compares the advantage and disadvantage between the two methods. To unify the two methods under traditional current decoupling control, an individual phase control method using the mix of zero-sequence and negative-sequence currents injection is proposed, and on the basis of which, the paper presents an interphase DC voltages balancing algorithm combing the two methods. The feasibility and validity of this algorithm are verified by simulation and experiment, and the results show that both the output performance and power adjustment ability of inverter can be taken into consideration.更多还原